There have been known hybrid vehicles including an internal-combustion engine (an engine) and a motor as a drive source of the vehicle. In the hybrid vehicle, a drive mode using only an engine, a drive mode using only a motor, and a drive mode using both the engine and the motor can be switched. In such hybrid vehicles, intermittent operation during which the stop and the start of the engine are repeated is executed in accordance with the travelling state of the vehicle.
Also in the hybrid vehicle, a learning control of the engine is executed. For example, the idle speed control (ISC) that makes the rotation speed of the engine during idling operation (the idling speed) equal to a target rotation speed is executed. For example, the ISC learning that learns the opening degree of a throttle valve (the throttle opening degree) during the operation of the engine and reflects the obtained value to the throttle opening degree is executed, as disclosed in, for example, Japanese Patent Application Publication No. 2009-040234.